Patients have now been admitted to the primary protocol for the treatment of non-Hodgkin's lymphoma, and the goals of this protocol, namely, to define different prognostic groups within this broad category of patients have largely been achieved. Utilizing a CHOP - high dose methotrexate regimen, the results in lymphoblastic lymphoma without marrow involvement and patients with entirely resected intraabdominal undifferentiated lymphoma or localized disease have been excellent (currently 82% and 90% disease-free survival). There is a suggestion that for some sub-groups of lymphoblastic lymphoma (namely patients with a large mediastinal mass) this protocol may be superior to the widely used LSA2 L2 protocol. Among the remaining patients the most important prognostic features are soluble interleukin-II level and bone marrow involvement. Current focus is on high risk patients with undifferentiated lymphomas, defined as all patients other than those with localised disease (stage A) or completely resected disease (stage AR). These patients are being treated on an intensified version of 7704 while a new drug combination of ifosfamide, VP16 and high dose ara-C is evaluated in relapse patients. Because of the evident activity of the relapse protocol, we are planning a new primary protocol incorporating the new drug combination. Several centers have expressed an interest in participating in this study. We should also incorporate molecular analysis of tumors into the new protocol in an attempt to refine further our ability to sub-categorize undifferentiated lymphomas.